1. Field of the Invention
The present invention relates to a head-protecting airbag mountable on vehicle for protecting occupant's head, which, when fed with inflation gas, is deployable downward from upper periphery of side windows to cover the interior side of the windows.
2. Description of Related Art
In the prior art, Japanese Patent Laid-Open No. 2004-299483 is illustrative of ahead-protecting airbag folded and housed in the upper periphery of windows inside the vehicle. When fed with inflation gas, the airbag deploys downward and covers the vehicle's interior side of the windows. The airbag is provided, in its upper edge as completely inflated, with a plurality of mounting portions for attachment to the upper periphery of the windows. Each of the mounting portions includes a mounting hole.
This airbag is manufactured by hollow-weaving method. The airbag includes a gas admissive portion which admits inflation gas therein and inflates to separate its vehicle's inner wall and vehicle's outer wall, and a non-admissive portion which admits no inflation gas. The gas admissive portion includes a protective portion which inflates to cover windows. The non-admissive portion includes a peripheral portion encircling the gas admissive portion, and mounting portions.
Each of the mounting portions is coupled with a pair of holder plates, which are made of sheet metal and applied to both inner and outer sides of the mounting portion. The mounting portion is attached to the inner panel of vehicle body by inserting a bolt serving as mounting means through the mounting holes formed in the mounting portion and the holder plates, and fastening the bolt into a nut attached to the inner panel.
As described above, the mounting portions are bolt-fixed to the vehicle body utilizing the holder plates, in the head-protecting airbag of this kind. That is, the holder plates hold periphery of the mounting hole of the mounting portion by fastening by the bolt. With this construction, even if a strong downward tension force is rapidly applied to the mounting portions upon airbag inflation, the holder plates serve to counteract the tension in a bolt-fixed state. As a result, the mounting portions of the hollow-woven airbag are stably secured to the vehicle body by the holder plates.
In the case where the holder plates are not used to attach the mounting portions of the head-protecting airbag to the vehicle body, clips can be used as mounting means, for example. However, unlike the case of bolts, clips exert less holding force to hold down the periphery of the mounting hole of the mounting portion. Accordingly, if a strong downward tension force is rapidly applied to the mounting portions upon airbag deployment, the force directly acts on the inner circumference of each of the mounting holes, so that the mounting portions made of fabric may be torn in its edge opposite from the acting direction of the tension force, which may detach the mounting portions from the vehicle body.